Stoneflies

Stoneflies are not as important to the fly fisherman as are the mayflies, caddisflies or midges. However, the giant "salmonfly" hatch can provide some exciting fishing opportunities. None the less, it is a good idea to carry a few stonefly imitations in the fly box as you do need to be prepared when fish are feeding on stoneflies. To reduce the number flies in your box, I would suggest that you carry a few suggestive patterns in various sizes and colors.

Stoneflies come in a wide range of sizes, perhaps the widest range of sizes of any aquatic insect. Nymphs and adults can range from over 2" (50 mm) to as small as ¼" (6 mm). Hook sizes can range from #8 to a #4. The most common range is #10 1XL to a #6 3XL.

Stoneflies have an incomplete life cycle - egg, nymph and adult. The length of the life cycle can depend upon the family or species. The smaller stoneflies usually have a shorter life cycle of one year. The larger stoneflies may have a life cycle that can last up to four years. The majority of the cycle is spent in the nymphal stage. As the nymphs prepare to emerge, they migrate to the shore and crawl out on a rock, twig or foliage before completing the transformation from nymph to adult. The nymph is especially vulnerable to be eaten by fish at this time. Adults mate on the shore with females returning to the water to lay eggs. Some species fly above the water dropping eggs into the water, other species dance above the water dipping their tails into the water to loosen eggs, yet other species dive into the water releasing their eggs on the bottom. Adults are most available to fish in the egg laying stage.

Because of their primitive gill structures, stoneflies favor flowing water. They have a preference for cool streams and spring waters. Some species can be found in lakes - usually well-oxygenated high mountain lakes.

Because of their similar behaviors, stoneflies can be divided into five groups based upon size and color differences. This breakdown can be useful in simplifying fly selection for adults and nymphs.

Tying Stonefly Patterns

Nymphs - A stonefly nymph is tied much like a mayfly nymph. The stonefly nymph has two tails which are usually represented by goose biots. The body differs from a mayfly in that the stonefly gills are located under the area on or about the thorax at the base of the legs. The wing pad can be represented by various materials to include turkey tail barbs, pheasant barbs, thin skin, etc. The body and thorax areas are about equal in length. The stonefly has three pairs of legs - three on each side.

Adult - Stone fly adults most prominent feature is probably the wings. At rest the wings lay flat against the body. In flight stoneflies are clumsy fliers with wings that are prominent. A good general pattern to represent a stonefly is the Stimulator.

Little Brown

Recognition: Nymphs lack gills or have only a few finger like filaments positioned under the head. Many species have numerous long hairs on their legs and body. Both nymphs and adults have three shallow notches along the outer margin of the labium. Because of the diversity (260+ species) it is difficult to identify them even at the family level.

Size: Small, less than �� long

Habitat: Little Brown Stoneflies are a major component of mountain streams. They also occur in large rivers when the substrate is smaller and temperatures are warm.

Little Yellow Stonefly

Recognition: The adults range in color from bright yellow to brownish orange while the nymphs are yellow to light brown with very distinctive dark stripes or irregular markings on the abdomen and thorax. One family has a distinctive roach-like shape and all have two tails.

Size: Ranges in size from �� to ��.

Habitat: Gravel or rock riffle areas provide the best habitat. Although some seem to prefer spring creeks where moss beds or plant debris covers the bottom. Streams must remain cool and well-oxygenated all year for really good populations. The greatest abundance are found in the East and the mountain areas of the West.

Little Green Stonefly

Recognition: Little Green Stonefly nymphs are uniformed green or brown in color, with brown the most common. Gills are absent from all Little Green Stoneflies and their tails are short. Adults vary in color from bright green to pale yellow.

Size: The nymphs range in size from �� to �� while the adults are from 3/8� to ��.

Habitat: Not common in the central part of the country, but can be abundant in the eastern and western sections. Cool streams provide the best habitat. Riffle area with moderate to slow currents where plant debris collects is the ideal habitat for many species. Adults are found on the stream side foliage.

Golden Stonefly

Recognition: Nymphs have distinctive dark markings on the thorax segments and gill tufts at the base of each leg. They range in color from pale yellowish tan to dark brown. Adults are similar in size to the nymphs. Many are rich golden brown, while other species are a dark brown color.

Size: Large reaching lengths of 1� � 2�.

Habitat: Golden Stoneflies are distributed across the country, but the best hatches occur from the Rocky Mountains to the Pacific Coast. Good populations occur in both small streams and large rivers. Riffles and rocky substrate provide the best habitat. Golden are the most widespread and abundant large stoneflies.

Giant Stonefly

Recognition: Nymphs are recognized by their large size, uniform dark brown to black color, and gill tufts extending to the underside of the first two or three abdominal segments. They have a rounded body and shorter tails than most stoneflies. Adults appear dark brown or black in color, but the underside of the body has colors ranging from reddish-orange to pale tan.

Size: Giant Stoneflies are the largest stoneflies in North America. Nymphs range in size of 50mm (2�) to 75mm (3�).

Habitat: Areas with moderate current and a rocky bottom that traps plant debris provide excellent habitat. Giant Salmon Flies and Giant Black Stoneflies tend to be most common in moderate- to large-sized rivers (Big rivers, Big flies). Small Salmon Flies are more common in small streams and creeks.